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Physical Science 20 Turn in Assignment #4 – Light
1. What is the index of refraction of a liquid in which the speed of light is 2.50 x 108m/s. 1.20
2. The index of refraction of a diamond is 2.42. What is the speed of light in diamond? 1.24 x 108m/s
3. Light passes from air into diamond with an angle of incidence of 60°. What will be the angle of refraction?
21°
4. A transparent substance has a refractive index of 1.30. What is the angle of incidence in air when the angle
of refraction in the substance is 45°? 67°
5. Light travels from medium A to medium B. The angle of refraction is less than the angle of incidence.
a) Which medium has the higher index of refraction?
b) In which medium does the light travel at a lower speed?
6. What is the index of refraction of a material if the angle of incidence in air is 50° and the angle of refraction
in the material is 40°? 1.19
7. The speed of light in plastic is 2.0 x 108m/s. What is the refractive index of plastic? 1.5
8. The index of refraction of glass for violet light is 1.53 and for red light is 1.51. Assuming that the velocity
of light in a vacuum is 3.00 x 108m/s, what are the speeds of violet light and red light in glass?
1.96 x 108m/s and 1.99 x 108m/s
9. Using Snell’s Law determine the index of refraction when the angle of incidence and refraction are
a) 50° & 30°
b) 30° & 18°
c) 60° & 38°
10. A ray of light in air strikes a block of quartz at an angle of incidence of 30°. The angle of refraction is 20°.
What is the index of refraction of the quartz? 1.46
11. Light travels from air into water. If the angle of refraction is 30°, what is the angle of incidence? 42°
12. A ray of light passes form air into water (nw = 1.33) at an angle of incidence of 50°. What is the angle of
refraction? 35°
13. One ray of light strikes a diamond (nd = 2.42) and another strikes a piece of fused quartz (nq = 1.46) at
angles of incidences of 40°. What is the difference between the angles of refraction? 11°
14. A ray of light strikes a block of polyethylene (np = 1.50) with angles of incidence of a) 0° b) 30° c) 60°.
Determine the angle of refraction in each case.
15. To spear a fish you must aim below the apparent position of the fish. Explain
16. A ray of light passes from water into carbon disulphate (nc = 1.63) with an angle of incidence of 30°. What
is the angle of refraction in the carbon disulphate? 24°
17. The speed of light in three different media is as follows: a) 2.25 x 108m/s b) 1.24 x 108m/s c) 1.95 x 108m/s.
Determine the index of refraction of each medium and using the table on page 353 identify the type of
medium in each case. a) 1.33 b) 2.42 c) 1.54
18. Relate each number in the diagram below to one of the following terms: angle of incidence, normal,
refracted ray, angle of reflection, incident ray, angle of refraction, reflected ray.
2
1
3
4
5 6
8
7
9
10
19. What is the critical angle if the index of refraction for a medium is 1.68? 36.5°
20. What is the index of refraction of a medium if the critical angle is 40°? 1.58
21. Is the critical angle for glass with an index of refraction of 1.53 greater or less than that for glass with an
index of refraction of 1.60? Determine the critical angle for each. 40.8°, 39.7°